Stoker



Dec. 17, 194o B. M. Gomma STOKER Filed May` e, 1937 Patented Dec. v1 7, 1940 UNITED sTATEs STOKER Bernard Morse Guthrie, Chicago, lll., assignor to Fairbanks, Morse & Co., Chicago, Ill., a corporation of Illinois Application May s, 1931, serial No. 141,046

2 claims. (c1. 19g-s4) This invention relates to improvements in fuel feeding mechanism for stokers and the like, the invention having particular application to stokers of the under-feed type.

An object of the invention is found in the provision of' an improved fuel feed mechanism for stokers, which through a novel construction and arrangement of the fuel feeding parts, attains an efficient and positive transfer of fuel through the feed'conduit, and overcomes the tendency for the fuel to pack to an undesirable degree, in the con- Another object resides in the provision of an improved fuel feeding mechanism including a conveyor tube or'conduit extending between a retort and a sourceof fuel supply, such as a hopper or bin, and a fuel conveyor operable in the conduit, the conduit being formed to provide zones of reduced internal diameter near each end thereof and a zone of increased internal diameter intermediate its ends, whereby to attain.

desired conditions of fuel feed therethrough.

Another object is attained in the provision, in

combination with a conveyor tube or conduit of the formabove noted, of a conveyor device of helical or screw type located within the conduit, the screw conveyor being formed of sections differingv in the pitch of the helical flights or screw blades thereon, whereby to improve the function of the conveyor, in cooperation with the novel form of conduit in which itV operates.

A further object is -attained in. the provision, in combination with a screw conveyor of the improved form above noted, which is extended through the lower portion of Va retort and projected therebeyond for connection t operating mechanismtherefor, 'of a screw sc 4of reversedflights for preventing the conveya ce of fuel beyond the retort, and bearing means for the conveyor adjacent the reversed flights. Further objects and advantages will appear from the following description and from the drawing, in which:

Fig. 1 illustrates a stoker system embodyingthe features of the invention, certain parts of the fuel feeding mechanism being shown in section to more clearly disclose certain ofthe improved features, and Fig. tion of a part of line 2-2 in Fig. 1.

Referring to the drawing by suitable characters of reference, I designates genera11y.'a retort or burner assembly of the under-feed type. The retort assembly includes an upwardly opening nre pot I3 having a tubular, fuel-inlet Vextension I I 2 is an enlarged transverse sec-v the mechanism, as viewed from near the lower or bottom end and on one side thereof, and a similar tubular extension I2 on the opposite side of the fire pot and in axial alignment with the extension I I.v A fuel conveyor I4 extends from a fuel hopper or bin I5 through the extension I I, beneath the repot and through the extension I2 for coupling to a conveyor driving mechanism denoted generally at I8. In order to agitate the fuel in the bin I5 soas to assure fuel pick-,up by the bin end of the fuel conveyor I4, there may be provided within the lbin, a suitbeof any well known type, as a spoked wheel suitably supported and arranged for rotative acable agitator member Il. The agitator I1 may tuation by contact with the adjacent flights on 15 the conveyor I4, in Aaccordance with prevailing practice. The conveyor I4 is shown as comprised of three sections I8, I9 and v20, coupled together as at 22 and 23. In practice, the number of conveyor sections utilized will depend upon the dis- Y tance between the retort III and fuel bin I5.

As shown, the bin structure includes a bearing 24 for the end of the conveyor, and a front wall 26 having a fuel outlet 2IA through which the conveyor extends. Externally of the bin wall 28 and in register with the outlet 21 is a housing 28 which is open at its upper end. Such open end is normally closed by a cover 38 removably s'ecured to the housing 28 by suitable wing nuts 29.

of the housing 28 for removing spikes and other l deleterious material collecting therein which if not removed, might cause damage to the conveyor and its driving mechanism. 'Extending between Athe housing 28 and the fire pot extension II is a tubular casing or conduit structure enclosing the conveyor I4'. The conduit is comprised, by preference, of a section 3l connected in any suitable manner to the housing 28, the internal diameter of this section being such as to effect a minimum clearance with respectto the conveyor section I8 extending therethrough; a section 32 similar in form to the section 3I, connected in any suitable manner to the extension II, and a number of intermediate sections 34 of uniform internal diameter b'ut larger than that of either of the end sections ,V3I and 32. The internal diameter of the extension I I is by preference, substantially the same as thatof the conduit section 32, while theinternal diameter of the housing 28 when 35 having screw fllghts-ozahelical blades 36 of a predetermineddiameter and `flights 38 of greater diameter.' The nights 3i are located within the also. to prevent leakage gases and smoke from bin I 5, while the nights 33 extend partly within` the retort, from flowing into the bin.

the bin, through the housing 28 and the conduit The fuel leaving the conduit section 3| and section 3| and partly within the adjacent conduit conveyed through the sections 34, wiilbe con- 5 sections 34. The blades 36 and 3l are by prefducted through these sections by the conveyor at -5 erence, of equal pitch, as shown. Conveyor seca more rapid rate, by reason of the increased tion I9 which is disposed wholly within the conpitch of the screw nights 4l and 43 over that of duit sections 34, is comprised of a shaft 33 havnights 3l. Also. the fuel conveyed through coning screw nights 40 thereon of a diameter subvduit sections 34 will be substantially loosely fed l0 stantially equal to that of nights 38, but the pitch therethrough by reason of the increased inter- 10 of these nights is greater than that of nights 36 nal diameter of these sections over the conduit and 38, to enect a more rapid feed of fuel through section 3|, resulting in a greaterclearance be'- the conduit sections 34. Thus as shown in Fig. 1, tween sections 34 and`the'conveyor nights 4I and theV conveyor nights 33 are characterized by a 43. The increased rate 0f fuel feed thl'bllsh the '15 pitch A, whilethe nights 40 are characterized by conduit sections 34. as attained by the greater 15 a. predetermined greater pitch B. The conveyor pitch of the conveyorscrew nights therein, serves section which extends through the vlower por- 'also to prevent jamming ofthe fuel in these section of the nre pot I3, is comprised of a shaft 42 tions. having nights 43 thereon substantially equal in By l'eSOn 0f the' mil1imum clearance between 20 diameter and pitch' to the nights 40, these nights the @livel/0l' nights u and theonduit section 20 terminating at 44 within the nre pot. Reversed 32 and refiQl't extension Il, the fuel fed therescrew nights 46 are formed on the end portion through Wlgl 06001119 Slightly packed and will be 41 of shaft 42, these nights and the shaft end 41 thus fed to the retort in a positive manner. The being disposed Within the extension I2 and within Packing 0f the fuel at this Zone in the-COUVES'OY a tubular casing` 43 extending between the ex- 00115111115 SIUCUI'B. Serves t0 prevent to a large 25 tension and a. housing 50 for the conveyor drivdegree. il ,bk 110W 0f 8858s und Smoke from the ing mechanism I6. The reversed nights 46 serve remito to return to the nre pot any fuel which may enter The P50508 0f the fuel in the zones of the the extension Iz. It will be noted that the re- Conduit Sections 3| and 32 is relatively slight. but

3 versed flights terminate at 5| in the nre pot and Suiiicieni i0 attain the purpose therefor, as here .30 spaced from the termination 44 or the fuei feedinbove deciibed- The desree of packing is, ing nights 43. 'I'hus the portion 52 of the shaft however, not such as to impose undue Stress 1111011 42 disposed centrally of the lower portion of the 0i 109111118 0f the wnveyor and its driving mechnre pot is free of screw nights.- Moreover, it will mism which otherwise might aus@ damage t0 35 he observed that the oppositoiy directed nights the convenir 0r .stoppage ihm! dueioimmina 35 43 and 46'wil1 coaci;A to direct and urge the fuel It is t0 be understd that in! number 0f C021- upwardiy in the nre pot, thus to eireoi a positive 'duit .Seciiiim 34 wd conveyor sections i9 may be delivery of fuel thereto. utilized. dependins upon the Adistance location of The shaft end 41 is ooupied as at 54, to a oonthe remi i relative i0 the Bouwe of fuel supply. 4o veyor driving element 55 which is operatively assuch as the bm 'l A150 it 18.1'0 be noted that 40 sociated (not shown) with the driving mechathe structural futures and mnemell: 0f the nism |6. Adjacent the coupling 54 are a pair of parts compsin the fuel feeding System may be disc elements 56, one thereof being carried by thev altered or modmed Without departing from the Shaft end 41 and the other by the element ss. -Silfii and full intended Scope 0f the invention. as

'Ihe diameter of these discs conforms closely to degni-31125, the appended claims' the internal diameter of the casing 4s (Fig. 2), c

whereby the discs may serve as bearing elements for the conveyor shaft. 'I'he discs serve also, to domestic type comprising a nveyor shaft' a' 50 tclllsitlthuggsmg 48 against movement of fuel non of said nights being of s predtermmed di 50 As appears in Fig. 1, the mechanism enclosed by the housing 5o includes in addition to the ugefhsnfirftgfw ma 0; magg;

conveyor driving mechanism I3, a suitable blower pitch temmatmg' inwardly m o ne Il. e artistes.;situaties www avm-nam anism I6 in any suitable manner, as by the belt connection shown in broken lines at 6|, delivers cnxgllneginssdaogimmlgng combustion air to the burner through an air conthan the diameter ofthe ments en10sd,there- V duit 62 leading to and communicatingwith the by, to pmvide a, substantial operating clem-ame G0 burner air Chamber l therebetween, whereby to facilitate an unrestrict- The flmtinl '0009010451011 between the im* ed conveyance of fuel therethrough.' und spaced proved conveyor and thenovel form of conveyor conduit sections, of relatively short longitudinal conduit will be now described. The screw nights extent, the interna] diameter of mh of the 1M- e5 3E and 33 conduct fuel from the hopper or bin, ter being restricted relative to the other conduit 05 through the housing 28 and through the conduit sections. to provide a minimum operating clearsection 3l into the conduit sections 34. VBy reaance with the night portions enclosed thereby, son of the larger diameter of nights '3l relative whereby to enect a Decking of the fuel conveyed to that of nights 3l, and the minimum clearance through the restricted conduit sections.

between these nights and the housing 2l and 2. A fuel conveying assembly for stakers of do- 70 conduit section 3|, a slight packing of the fuel meetic type, comprising 'a conveyor shaft, fuel- Occurs through this 2011. resultins in a Positive conveying means on said shaft, including a secmovement of fuel through the binoutlet, houstion of helical nights of a predetermined diaming 28` and conduit section 3|. 'I'h slight packeter and pitch, a second section of helical nights 15 ing of the fuel through the described zone, serves of greater diameter, contiguous to said first sec- 75 tion, and a. third section of helical ilights of section of greater internal sectional area, prosubstantially the same diameter as the ights of vidingA a-substantial operating clearance for the said second section, but of greater pitch, said last conveyor flights enclosed thereby, and an opposection terminating inwardly of one end of the 'site end section of restricted internal sectional 5 shaft, and a conduit structure enclosing a subarea substantially equal to that of said rst con' 5 stantial portion of said fuel-conveying means and l duit end section, said last end section cooperatcomprised of an' end section having a restricted ing with flight elements of` said third iiight secinternal sectional area cooperating with said section to eect a minimum operating clearance ond section of helical nights to effect a minimum therebetween.

v10 operating clearance therewith, an intermediate ERNARD MORSE GUTHRIE. 16 

